sdu faculty of forestry journal special edition 2009 - Orman Fakültesi

SDU Faculty of Forestry Journal
Serial: A, Number: Special Issue, Year: 2009, ISSN: 1302-7085, Page: 261
ARE SUBPOPULATIONS OF Heterobasidion parviporum
DIFFERENTIATED BY LOCAL CLIMATE?
Michael M. MÜLLER 1* , Nicola LA PORTA 2 , Jaana EKOJÄRVI 1 , Jarkko
HANTULA 1 , Kari KORHONEN 1
1 Finnish Forest Research Institute, Box 18, 01301 Vantaa, Finland
2 IASMA Research and Innovation Centre, Fondazione Edmund Mach, Environment and
Natural Resources Area, Via E. Mach 1, S. Michele all'Adige 38010, Italy
* Michael.mueller@metla.fi
We determined the decomposition rate (DR) of spruce wood by representatives
of different subpopulations of Heterobasidion parviporum at various temperatures.
Sixty three H. parviporum isolates originating from geographically distant and
climatically varying environments (Finland, Denmark, Italy and Central Siberia)
were cultivated at eight temperatures between 6 o C and 33 o C on Norway spruce saw
dust as the only substrate. Decomposition activity was determined as the
production of carbon dioxide. The optimal temperature for decomposition varied
considerably between the isolates and ranged between 20 o C and 30 o C. The activity
of all isolates decreased drastically at temperatures from 30 o C to 33 o C, being at
33 o C only 7 % of that at 30 o C. The highest between-isolate variations in DR were
at the extremes of the applied temperature scale, at 33°C and 6°C.
The DR of the four subpopulations did not differ significantly from each other
at any temperature, neither was found any variation according to the age of the
cultures (0.3 - 16 y) (ANOVA). However, the Italian and Siberian isolates were
collected from several locations in which the climate varied considerably, and the
highest monthly average temperature of each district explained partly the DR of the
isolates at 6 o C (p = 0.017). When only the Italian isolates were included in the
ANOVA, a similar significant variation was found (p = 0.043, n = 15). The highest
monthly average temperature of the location correlated negatively with the DR of
H. parviporum at 6 o C. Hence, local climate affects significantly the DR of H.
parviporum.
Gene variation of different isolates was studied with six microsatellites and by
determining the DNA sequences of three sequence characterized amplified regions.
Interestingly, no significant genetic variation was found between Italian, Danish
and Finnish isolates. This suggests that there is significant gene flow between these
subpopulations of H. parviporum, and that the variation in DR at 6 o C between
isolates from different localities may be a consequence of other factors than
restricted gene flow.
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